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Subject: Re: [PATCH] mm, debug, kasan: save and dump freeing stack trace for
 kasan
To:     Vlastimil Babka <vbabka@suse.cz>,
        Walter Wu <walter-zh.wu@mediatek.com>
Cc:     Qian Cai <cai@lca.pw>, Alexander Potapenko <glider@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Andrey Konovalov <andreyknvl@google.com>,
        Arnd Bergmann <arnd@arndb.de>, linux-kernel@vger.kernel.org,
        kasan-dev@googlegroups.com, linux-mm@kvack.org,
        linux-arm-kernel@lists.infradead.org,
        linux-mediatek@lists.infradead.org, wsd_upstream@mediatek.com
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 <d98bf550-367d-0744-025a-52307248ec82@suse.cz>
From:   Andrey Ryabinin <aryabinin@virtuozzo.com>
Message-ID: <28e076ed-d4c2-c29d-f0cb-b976e8c0725a@virtuozzo.com>
Date:   Wed, 25 Sep 2019 12:41:18 +0300
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On 9/23/19 11:20 AM, Vlastimil Babka wrote:
> On 9/16/19 5:57 PM, Andrey Ryabinin wrote:
>> I'd rather keep all logic in one place, i.e. "if (!page_owner_disabled && (IS_ENABLED(CONFIG_KASAN) || debug_pagealloc_enabled())"
>> With this no changes in early_debug_pagealloc() required and CONFIG_DEBUG_PAGEALLOC_ENABLE_DEFAULT=y should also work correctly.
> 
> OK.
> 
> ----8<----
> 
> From 7437c43f02682fdde5680fa83e87029f7529e222 Mon Sep 17 00:00:00 2001
> From: Vlastimil Babka <vbabka@suse.cz>
> Date: Mon, 16 Sep 2019 11:28:19 +0200
> Subject: [PATCH] mm, debug, kasan: save and dump freeing stack trace for kasan
> 
> The commit "mm, page_owner, debug_pagealloc: save and dump freeing stack trace"
> enhanced page_owner to also store freeing stack trace, when debug_pagealloc is
> also enabled. KASAN would also like to do this [1] to improve error reports to
> debug e.g. UAF issues. This patch therefore introduces a helper config option
> PAGE_OWNER_FREE_STACK, which is enabled when PAGE_OWNER and either of
> DEBUG_PAGEALLOC or KASAN is enabled. Boot-time, the free stack saving is
> enabled when booting a KASAN kernel with page_owner=on, or non-KASAN kernel
> with debug_pagealloc=on and page_owner=on.
> 
> [1] https://bugzilla.kernel.org/show_bug.cgi?id=203967
> 
> Suggested-by: Dmitry Vyukov <dvyukov@google.com>
> Suggested-by: Walter Wu <walter-zh.wu@mediatek.com>
> Suggested-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---

Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>